If by 'Simple' your goal is to serve static web pages (ie, no support for php, cgi, or fancy stuff), then I switch recently to Fenix web server (Nodejs based I think), (I found it after being fed up with encoding issues on Windows with Python SimpleHttpServer)
Since I gave it a try, I haven't switched to anything else (unless need for more, in which case I'm more using Docker container in VMs, so that you have the same configuration no mater the host)